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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

916 results found.

  1. GRB 230520A: MAXI/GSC detection
  2. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  3. GRB 230510B: Fermi GBM detection
  4. GRB 230510B: AstroSat CZTI detection
  5. GRB 230510B: CALET Gamma-Ray Burst Monitor detection
  6. GRB 230510B: MAXI/GSC detection
  7. MAXI GRB230408.82: Global MASTER-Net observations report
  8. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  9. GRB 230307A: soft X-ray detection with LEIA
  10. GRB 230307A: MAXI/GSC upper limit
  11. GRB 230220A: Correction to GCN 33352
  12. GRB 230220A: MAXI/GSC detection
  13. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  14. GRB 230204B: ATCA radio detection
  15. GRB 230204B: MASTER early OT detection
  16. GRB 230204B: Swift/UVOT Upper Limits
  17. GRB 230204B: Fermi GBM detection
  18. GRB 230204B: Swift-XRT afterglow detection
  19. GRB 230204B: 3.6m DOT optical observation
  20. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  21. GRB 230204B: Swift ToO observations
  22. GRB 230204B: Detection by GRBAlpha
  23. GRB 230204B: AGILE detection
  24. GRB 230204B: GIT discovery of the likely optical afterglow
  25. GRB 230204B: AstroSat CZTI detection
  26. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  27. GRB 230204B: MAXI/GSC detection
  28. GRB 230111A: Fermi GBM Observation
  29. GRB 230111A: MAXI/GSC detection
  30. GRB 221028B: MAXI/GSC detection
  31. Konus-Wind detection of GRB 221017A
  32. GRB 221017A: CALET Gamma-Ray Burst Monitor detection
  33. GRB 221017A: Swift-XRT observations
  34. GRB 221017A: Swift ToO observations
  35. IPN triangulation of GRB 221017A (long)
  36. MAXI GRB221017.24: Global MASTER-Net observations report
  37. GRB 221017A: MAXI/GSC detection
  38. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  39. MAXI GRB 221006A: Redshifts of the possible host galaxies
  40. GRB 221006A: Swift-XRT afterglow detection
  41. Afterglow limits of GRB 221006A from OHP
  42. GRB 221009A: NICER follow-up observations
  43. GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
  44. GRB 221006A: Swift ToO observations
  45. GRB 221006A: CALET Gamma-Ray Burst Monitor detection
  46. GRB 221009A BOOTES-2/TELMA and OSN optical detections
  47. GRB 221008A: Swift-XRT observations
  48. GRB 221008A: Tiled Swift observations
  49. GRB 221008A: MAXI/GSC detection
  50. GRB 221006A: Swift-XRT observations
  51. GRB 221006A: Tiled Swift observations
  52. GRB 221006A: MAXI/GSC detection
  53. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  54. MAXI GRB220706.73: Global MASTER-Net observations report
  55. Trigger 1113743: Swift detection of MAXI J0655-013
  56. Swift Detection of MAXI J0655-013
  57. MAXI GRB220607.31: Global MASTER-Net observations report
  58. MAXI GRB220607.41: Global MASTER-Net observations report
  59. Konus-Wind detection of GRB 220506A
  60. Konus-Wind detection of GRB 220514B
  61. GRB 220514B: Swift-XRT observations
  62. GRB 220514B: Tiled Swift observations
  63. GRB 220514B: MAXI/GSC detection
  64. MAXI GRB220514.98: Global MASTER-Net observations report
  65. IceCube Alert 220513.97: Global MASTER-Net observations report
  66. GRB 220506A: MITSuME Akeno optical upper limits
  67. GRB 220506A: GIT optical upper limit.
  68. GRB 220506A: BOOTES-5/JGT optical upper limit
  69. GRB 220506A: Swift-XRT afterglow detection
  70. GRB 220506A: Tiled Swift observations
  71. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  72. MAXI GRB220506.27: Global MASTER-Net observations report
  73. GRB 220412A: Swift/UVOT Upper Limits
  74. GRB 220403C: Swift-XRT observations
  75. GRB 220310A: MITSuME Akeno optical observation
  76. IPN triangulation of GRB 220310A
  77. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  78. Konus-Wind detection of GRB 220310A
  79. GRB 220310A: GIT confirmation of optical afterglow.
  80. GRB 220310A: MASTER optical counterpart detection
  81. GRB 220310A: Swift ToO observations
  82. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  83. GRB 220310A: MAXI/GSC detection
  84. MAXI GRB220310.02: Global MASTER-Net observations report
  85. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  86. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  87. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  88. GRB 211227A: MAXI/GSC detection
  89. GRB 211225A: MITSuME Akeno optical upper limits
  90. MAXI GRB211225.14: Global MASTER-Net observations report
  91. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  92. GRB 211218A: MITSuME Akeno optical upper limits
  93. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  94. MAXI GRB211218.04: Global MASTER-Net observations report
  95. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  96. GRB 211115A: MAXI/GSC detection
  97. Fermi trigger No 653072474: Global MASTER-Net observations report
  98. GRB 210818A: Swift-XRT refined Analysis
  99. MAXI GRB210709.93: Global MASTER-Net observations report
  100. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation

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